At a certain point in the war, the utility of the fighter-bomber was very well established, the Germans even had their own name for it, Jäger-Bomber I think it was, or Jabo. (I'd recommend the Wikipedia article, but it claims the P-38 was a poor fighter (!!!)).

In general Nazi procurement was extremely subpar at this level. One might think Arthur C. Clarke's https://en.wikipedia.org/wiki/Superiority_(short_story) was based on them.